MONTE-CARLO SIMULATION OF GRAIN-GROWTH

The temporal evolution and morphology of two-dimensional grain growth are simulated by Monte Carlo simulation techniques. In the simulation, the anisotropy of the grain boundary energy is incorporated into the model. Compared with the case in which no anisotropy of boundary energy is assumed, the suppression of grain growth is observed and the grain size and the edge number distributions become broad. The occurrence of the wetting phenomena is considered to be responsible for the broadness of the grain size distribution in the structure simulated by a model in which anisotropy of boundary energy is incorporated. The pinning effect of precipitates on growth kinetics is also studied by the model. The size of pinned grain is found to varied with inverse square root of the particle volume fraction. The size distribution of pinned grain structure is narrower than that of the pinning-free grain structure with the same anisotropy of grain boundary energy. The average size of n-sided grain is proportional to the grain edge number, n. The effect of the anisotropy of grain boundary energy on the n-dependence of the average grain size is not evident. The nearest neighbor sides correlation like Aboav-Weaire relation is observed in both grain structures computed by Potts model and modified Potts model. The conversion of Monte Carlo step to real time is attempted based on diffusion controlled mechanisms. The estimated grain size with use of the conversion formula in pure iron at 1 273 K is in good agreement with that evaluated by the empirical formula derived on the basis of experimental result.